Rupert Grint, best known as Ron Weasley in the Harry Potter films, is making his Broadway stage debut this fall in Terrence McNally’s farce, It’s Only a Play. The production is currently in rehearsals, and his co-stars include luminaries Stockard Channing, F. Murray Abraham, Megan Mullally, and Broadway’s golden boys, Nathan Lane and Matthew Broderick.

“The first few weeks, I just felt quite out of my depth, ’cause it is quite an overwhelming cast,” Grint told VF Daily, at a Tuesday-morning press conference at theater-district hangout Joe Allen. “I just feel so lucky that the whole company is just so experienced, and director Jack [O’Brien] is amazing—and Terrence. I’m so lucky to be surrounded by these people,” he said.

Grint had done one play previously, in London’s West End, and producer Tom Kirdahy was so impressed with the 25-year-old’s performance that he offered him the role of an angst-filled wunderkind director. “I’ve kind of spent a lot of time [with] a lot of different directors. Working on Potter, I had this wealth of very various different directors—Alfonso Cuarón, Mike Newell,” Grint explained. “But my character Frank is much more complicated, he’s deeply troubled, so it’s been interesting playing a character with issues. It’s fun.”

At the press conference, some of the big stars shared their impressions of Grint’s stage chops.

Megan Mullally actually hadn’t seen the Potter films, and didn’t know of Grint until now. “I didn’t read the books, and I’m old, so no, I didn’t really know who he was,” she told VF Daily. “But he’s adorable and lovely, and he was an absolute basket case for the first week or so. The first night when I met him, there was a little dinner, and he was standing outside, smoking a cigarette, and I was, like, ‘Are you Rupert?’ And he said he was, and he just instantly announced that he was terrified. I said, ‘Oh, you’re going to be great.’ He said, ‘I’m so intimidated.’ I said, ‘No, no. We should be intimidated with you.’” Mullally is pretty impressed with his work, so far. “I think he’s fantastic. I think he’s going to be great in this; he’s really good. Those goddamn Brits!”

“I have children, so I certainly know Rupert Grint,” said Matthew Broderick. “I always liked him in those movies. And then I remember meeting him at a premiere in New York—he does not remember, but I do—introducing him to my son, and he was really sweet,” the Tony Award–winner added. “And he’s lovely to watch. He’s such a good actor, and he’s so hardworking and diligent, and to see a young fellow get his first Broadway shot is just kind of a pleasure to watch.”

Nathan Lane says Grint is a natural stage actor. “And it’s wonderful, his part is a particularly showy role; he has a lot of funny stuff,” Lane told us. “What’s great for Rupert is it’s so the opposite of what he has played, what we know him best for in the Harry Potter films. He’s such a disagreeable character. He’s very unhappy, he’s angry about everything,” the Tony Award–winner said, laughing. “It’s pretty spectacular.”

Grint said that his Potter castmate Daniel Radcliffe’s turns on the Broadway stage have been inspiring. “It’s quite inspiring to see him just, alive, onstage. He absolutely loves it. I mean, he doesn’t really give me any, like, advice, but just watching him have so much fun has always kind of made me think about it.”